1. Field of the Invention
The present invention relates to semiconductor test apparatus and, in particular, to vibration resistant test modules for use with semiconductor device test apparatus.
2. Description of the Related Art
In the field of semiconductor device testing, a test module (also known as a tester load board, load module or performance board) is a mechanical and electrical interface used to connect a test system""s tester head to a semiconductor device (e.g., an integrated circuit) that is undergoing testing. Conventional test modules are adapted to interface electrically and mechanically with a variety of semiconductor device test apparatus components, including semiconductor device handlers and Device-Under-Test (DUT) cards.
FIG. 1 is a schematic representation of a conventional semiconductor device test apparatus 10 aligned with a conventional probing system 12. Semiconductor device test apparatus 10 includes a tester head 14, a fixture board 16, a test module 18, and a Device-Under-Test (DUT) Card 20. The tester head 14, fixture board 16, test module 18 and DUT Card 20 are mechanically and electrically interconnected in a conventional manner to route electrical signals from the tester head 14 to the DUT card 20.
A variety of tester heads, fixture boards, test modules, and DUT cards are known. For example, tester head 14 can be an XTS FT model tester head (available from Integrated Measurement Systems Inc.), while fixture board 16 can be a model 120-576100-01 fixture board (also available from Integrated Measurement Systems, Inc.). Furthermore, test module 18 can be, for example, a Model No. 95841032-768Pin Load Module (available from Schlumberger, San Jose, Calif.) and DUT card 20 can be, for example, a model No. 32-Z2-BY6-01 DUT Card (also available from Integrated Measurement Systems Inc.).
DUT card 20 is designed to hold a socketed semiconductor device 22 (also referred to as a Device-Under-Test [DUT]). It is also known in the field to conduct high volume testing of semiconductor devices by interfacing the test module 18 with a semiconductor device handler (not shown). Probing system 12 can be, for example, an optical probing system (OPS, such as a Model IDS2000 OPS available from Schlumberger, San Jose, Calif.) or an electron beam probing system.
The combination of a semiconductor device test apparatus and a conventional probing system, such as that illustrated in FIG. 1, can be employed to test and perform failure analysis on a semiconductor device. For example, an optical probing system or an electron beam probing system can be employed to generate signals and/or images (e.g., waveforms) from a predetermined region (e.g., a P-N junction region) of the semiconductor device. These signals and/or images are generated, while electrical signals are concurrently provided to the semiconductor device from the tester head via the fixture board, test module and DUT card.
A drawback of conventional semiconductor device test apparatus is that a significant amount of mechanical vibration can be transmitted from the relatively heavy tester head (and associated fans and balancing weights) to the semiconductor device. This vibration interferes with the ability of the probing system to accurately generate signals and/or images from the predetermined region.
Conventional test modules typically employ a plurality of relatively rigid pogo pins (e.g., 768 pairs of pogo pins for a total of 1536 pogo pins) arranged in a predetermined configuration known as the xe2x80x9cpin-outxe2x80x9d. These pogo pins serve as electrical connectors between such a pogo pin-based test module and a fixture board, as well as between the pogo pin-based test module and a DUT card. A conventional pogo pin 40, depicted in FIG. 2, is typically fabricated from solid steel or brass with a rounded end 42. Drawbacks of conventional pogo pins are that the rounded end 42 provides a relatively poor electrical contact area and the relatively rigid pogo pin transmits excessive vibration between the tester head and the semiconductor device.
Still needed in the field, therefore, is a test module for use with semiconductor device test apparatus that is resistant to vibration and that provides for a secure electrical contact between the test module and the semiconductor device test apparatus.
Test modules for use with semiconductor device test apparatus according to the present invention provide vibration resistance and a secure electrical connection between the test module and the semiconductor device apparatus. Such a test module includes a test module top plate, a test module bottom plate and a plurality of spring-and-wire assemblies.
The test module top plate and test module bottom plate each have a plurality of openings extending from their respective upper surfaces to their respective lower surfaces. Each of the plurality of spring-and-wire assemblies includes: (i) an electrically conducting wire with a top wire end and a bottom wire end; (ii) a top electrically conducting spring connector attached to the top wire end, and (iii) a bottom electrically conducting spring connector attached to the bottom wire end. Each of the spring-and-wire assemblies is threaded through separate openings in the test module top plate and test module bottom plate. The spring-and-wire assemblies are threaded such that the top electrically conducting spring connectors extend at least partially above the upper surface of the test module top plate, while the bottom electrically conducting spring connectors extend at least partially below the lower surface of the test module bottom plate.
Test modules according to the present invention employ the top and bottom electrically conducting spring connectors to make electrical connections between the test module and other semiconductor device test apparatus components, such as a fixture board, DUT card, and/or semiconductor device handler. These electrical connections are maintained by an elastic spring force of the top and bottom electrically conducting spring connectors. Since such electrical connections are compliant and spring-based, they provide vibration resistance and a secure electrical connection. In addition, the configuration of the spring-and-wire assemblies (equivalent to the xe2x80x9cpin outxe2x80x9d of a conventional load module) can be easily modified.